Scatter Shields

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Rob
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Scatter Shields

Post by Rob »

I've been perusing the rule book for a while and slowly building/planning on paper in preparation for the real deal.

Part of Rule 4.5.10 requires a 1/4" (6mm??) thick, 360' scattershield wide enough to shield the flywheel and clutch assembly.

In conversation at the lake a steel bellhousing was mentioned as a requirement as opposed to a fabricated scattershield protecting the required area outside of a non-steel bellhousing. The reason given was to prevent the trans front from falling and pole vaulting the vehicle in the event of a catastrophic failure.

Can one of the scrutineers clarify this for me please.

Cheers,
Rob
I owe, I owe, so off to work I go.
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BOB ELLIS
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Post by BOB ELLIS »

Rob,the rule seems self explanatory.1/4" thick steel,360'around clutch/flywheel. For your & the tracks safety,get a Lakewood / Mcleod scattershield. Dunno who said about the pole vaulting (thats olympics,not landspeed),its primary function is to contain a clutch/flywheel explosion.I've seen one (at Champion Dragway along time ago).the flywheel cut thru EVERTHING on its way out of the '55 Chevy,gearbox tunnel,dash, screen,etc.LUCKY not the drivers legs! also,get a billet(Explosion proof) flywheel,(yellaterra are pretty cheap still), & an explosion proof clutch (Not so cheap)
A fabricated 360',1/4" thick shield will get you thru.or even a ballistic blanket over bellhousing (Diest Safety / D.J Safety)with the correct rating will also get you thru.
Does this help?
Cheers , Bob.
Rob
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Post by Rob »

Thanks Bob and yes it does help.

Better to ask up front than go with my own interpretation/understanding.

There was no mention of the ballistic blanket in the rules but that will surely ease the pain, particularly in a space critical application. I'd figured on the steel flywheel but not the clutch so thanks there too. You don't take the whole rulebook in, even after multiple readings.

I've seen two vehicles pole vault, independently and oddly, both occured within 500m of each other. Both through driveshaft/uni failure not clutch/flywheel. I've also seen photos of a boat after it sheered the flywheel bolts and nothing was keeping that frisbee inboard let me tell you! :shock:

Cheers,
Rob
I owe, I owe, so off to work I go.
Dr Goggles
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Location: Right behind you Chief !

hellbousing

Post by Dr Goggles »

.it's worth considering making your bell-housing, rather than buying one and going through the grief of making the scattershield....... probably not an issue for most ......but it's what we're going to do.......
...few understand what I'm trying to do , but they vastly outnumber those who understand why..
David Leikvold
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bang!

Post by David Leikvold »

I've just had a quick look at the Lakewood website, they have two types of bellhousings / scatter shields. The red ones are scatter shields and are SFI approved, the black ones are transmission adaptors and are not SFI approved scatter shields. According to another site I found while looking for McLeod stuff they don't make SFI shields, they do transmission adaptors only. I haven't found any more about it yet so don't take my word for it. The Lakewood range was, not surprisingly, all about American engines only, which is fair enough, the commercial reality is there's no money in making oddball products for a tiny market. So if you intend to run anything Japanese, start designing your own scattershield and get a ballistic blanket as well, just in case it isn't as good as you'd hoped :wink:.
Of course another possibility would be to get an adaptor plate made for between the block and your chosen Lakewood scatter shield. That way you could choose one of about the right size and designed to fit the transmission of your choice, assuming you'd chosen an American trans. I supposed it wouldn't be any harder to make another adaptor plate or just re-drill the back of the scattershield for your transmission of choice if there wasn't one available off the shelf.
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David Leikvold
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Post by David Leikvold »

Good, Fast, Cheap, pick any two!
Rob
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Post by Rob »

Bob,

Assuming I manufacture my own bellhousing/shield of 1/4" mild steel, what testing would (if any) be required?

The ballistic blankets aren't all that expensive.

Cheers,
Rob
I owe, I owe, so off to work I go.
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BONES
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Post by BONES »

Rob
try real hard to fabricate or buy a steel scattershield.
I saw a flywheel come through an approved ballistic blanket at Heathcote last year or the year before. It was a rear engine dragster,so the driver was ok but a woman spectator was hit in the face by shrapnel as well as a bunch of other spectators.The ballistic blanket did nothing and rained down like feathers.
Maybe it couldn't cope with the sawing action of the ring gear.
cheers Bones
David Leikvold
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Post by David Leikvold »

That's the beauty of the salt, once you're off and running if the bits miss you they'll miss everyone. Don Garlits lost half of one of his feet when a clutch let go on him about 40 years ago. I think the idea would be to find a clutch that won't blow up (or is most unlikely to) and then get a small and light steel flywheel made to match. If you reduce the diameter significantly you can run it closer to the ground too, especially with a dry sump and a manual transmission. I also think it would be preferable to run a hydraulic thowout bearing so the only hole in the scattershield is just for the hydraulic line and not for a full sized clutch fork.
Good, Fast, Cheap, pick any two!
Rob
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Post by Rob »

Thanks Bones,

Point taken there.

Assuming my mental build becomes reality, there's no "buy" option.

David,

It wouldn't be too hard to fabricate a 1/4" slide to follow the fork and cover the hole in the housing. Much like the original sheet steel kept out most dirt and debris on some vehicles (Holdens maybe?? damned if I remember).. Now having said that, the hydraulic would certainly be a whole lot easier once correctly shimmed. That'd be a right PIA with no access point to measure through.

Cheers,
Rob
I owe, I owe, so off to work I go.
momec
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Post by momec »

Rob
I run a ballistic blanket but they are a last resort. Make a strong scatter sheid yourself.
Peter Perkins and Chris ? turned up with a front drive Astra this year and spent many many hours making an external scattershield only to find out its not required on front drive. Very difficult task on late model crap to create such a thing.
They were pis"ed off.
As Bob says read the rule book backwards, then start, then read it again.

Chris
Acme Racing #251
Rob
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Post by Rob »

G'day Chris,

That surprises me, why wouldn't a clutch explosion be an issue for FWD vehicles?

I doubt I could make a scattershield work without remodelling the floorpan so it'd have to be a fabricated bellhousing.

I need to add a line to my signature, "Nothing Worthwhile is Easy!"

Cheers,
Rob
I owe, I owe, so off to work I go.
OLDtimer
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Post by OLDtimer »

Chris, I am building a front wheel drive vehicle , but cant find in the rule book where it says scattershields are not required. To be on the safe side, however, i am plating the floor & firewall in front of me, just in case s..t happens. (Just because I cant find it, doesnt mean its not in there !) Pete. DLRA #6.
David Leikvold
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Post by David Leikvold »

I've never noticed any exemption for front wheel drives either. The only thing I can think of is that in a right hand drive car the line of an exploding flywheel would miss the driver, particularly as a stock aluminium bellhousing wouldn't deflect shrapnel to any noticeable degree. Too bad if you were standing in front of the car when it went bang. My Celica will have a custom made scattershield (probably made from a suitable diameter of steel drain pipe so that it is easy to make and doesn't look too bad either) whatever the rule actually is, although OT's idea would be safe enough for most situations, particularly if the car also used a trans blanket and was therefore legal anyway. Peter, what sort of car are you building?
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OLDtimer
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Post by OLDtimer »

My project is a 1989 Galant GSR running a 2.0 litre Evo 4 in production supercharged class. The flywheel is on the drivers side & I value my nuts, so will be fitting a blanket for sure ! Pete. DLRA #6
Last edited by OLDtimer on Tue May 12, 2009 8:36 pm, edited 1 time in total.
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